Such a method is known from S J Randolph et al., ‘Capsule-free fluid delivery and beam-induced electrodeposition in a scanning electron microscope’, RSC Adv., 2013, p 20016-23 [-1-]
Randolph describes the use of a liquid injection system (a nanocapillary) to deposit a droplet of liquid of CuSO4 solution in the low vacuum chamber of an environmental scanning electron microscope (ESEM). Capillary flow of the liquid is induced by bringing a nanocapillary into contact with a substrate. A microscopic droplet is then formed and stabilized (that is: its volume is kept approximately constant) by controlling the droplet evaporation rate with the substrate temperature (cooling the substrate with a Peltier heating/cooling stage) and by controlling the pressure of H2O vapor injected into the vacuum chamber. A focused electron beam is admitted to the droplet through a pressure limiting aperture so that the electron emitter of the scanning electron microscope can operate at a better vacuum than the vacuum in the low vacuum chamber. Electrochemical reduction of aqueous Cu2+ to solid, high purity, deposited Cu is achieved by using the capillary as an anode and the electron beam of the ESEM as a virtual cathode, enabling electrodeposition on both conductive and insulating substrates.
It is noted that the phrase ‘particle-optical apparatus’ is used to embrace electron microscopes (transmission electron microscopes, scanning electron microscopes, scanning transmission electron microscopes, etc.), focused ion beam machines (FIBs) and combination thereof.
The invention intends to provide an improved and more generic method of modifying the sample surface layer.